Beneficiation of acidic minerals



Patented Nov. 7,1944

UNITED STATES PATENT OFFICE snivnrrcmrrok or scmrc mans David W. Jayne, Jr., Old Greenwich, and Harold M. Day, Cos Cob, Conn, and Stephen E. Erickson, Calumet,

Minn, assignors to American Oyanamld Company, New York, N. Y., a corporation of Maine No Drawing. Application March 31, 1942,

Serial No.48'l,039

12 Claims. (01. cos-'16s) The present invention relates to mineral concentrations and more particularly relates to a nessis in connection with froth flotation processes of separating silica or silicate minerals, such as, mica, from non-metallic ores such as limestone, bauxite, barytes, limenite, calcite, and the like, and especially phosphate minerals whereinthe silicious gangue is floated away from the phosphate minerals.

In accordance with this invention natural ores or artificial materials comprising a mixture of acidic minerals with other mineral constituents are subjected to a separation or concentration process in the presence of a promoter for the acidic ore minerals, said promoter being a high molecular weight carboxylic' acid derivative of piperazine or a higher alkyl derivative of piperazine.

The reagents of the present invention are effective promoters or collectors for negatively charged or acidic ore materials, generally and said acidic material may either be worthless gangue o'r valuable ore constituents. The most important uses are, however, in connection with the froth flotation of silica from non-metallic ores in which the silicious gangue may represent a minor proportion of the ore rather than metallic and sulfide ores in which the gangue usually represents the major proportion of the ore. Representative acidic ore materials are the feldspars,

quartz, pyroxenes, the spinels, biotite, muscovite, clays, and the like.

The compounds which we have found to be useful in carrying out the present invention include broadly the products represented by the following general formula:

where X represents a higher alkyl radical, an alkylol ester radical, or an acyl radical of a higher molecular weight carboxylic acid and the salts of such compounds. It is to be understood that the a'cidyl radical is an acyl radical of a higher molecular weight carboxylic acid and that the alkyl radical is ,a higher alkyl radical, i. e., one containing from 8 to about 32 carbon atoms. .The acylated compounds which we. use in carrying out the process of the present invention can be veryconveniently prepared by the thermal reaction 01 piperazine with higher molecular weight carboxylic acids or by reacting piperaz'ine hydrohalides with alkali metal salts of higher molecular weight carboxylic acids. Similarly, the products may be prepared by thermally reacting esters of higher molecular weight carboxylic acids with piperazine. The following preparations will serve to illustrate methods for the preparation of certain representative compounds.

Higher monoacvl derivatives of piperazine A mixture of 21 grams of piperazine hexahydrate and 28 grams of oleic acid was heated in an open beaker with agitation to 200 0., then cooled to room temperature. The product was a brown paste readily and completely soluble in dilute acetic acid to give a clear solutio... This reaction product was converted to the acetate by adding to it 6 grams of glacial acetic acid.

Piperazine and coconut oil fatty acid (molar ratio 1:1)

A mixture of 21 grams of piperazine hexahy} drate and 21 grams of coconut oil fatty acids was ing preferably at least 8 and usually not more than 32 carbon atoms. It is also understood that the higher molecular weight acylating agents may be acids themselves, esters thereof, or halogen derivatives thereof. Among the sources of such acylating agents we may mention the following acids which, of course, will also include the esters and halogen derivatives of such acids.

These higher molecular weight carboxylic acids may either be saturated, unsaturated, or hydroxyl containing fatty acids, the preferred ones being those having at least 9 carbon atoms, such as for example, lauric, palmitic stearic, oleic, ricinoleic, capric, myristic," mixtures-of such acids, and especially mixtures of the fatty acids obtained from thefats and oils'of either vegetable or animal sources or their glycerides, such as those from coconut oil, olive ofl, peanut oil, flsh oils, and the like. Other suitable acids include talloel acids, petroleum acids, such as naphthenic acids and carboxy acids produced by the oxidation of petroleum, and the like.

The alkylated compounds which we use in carrying out the process of thepresent invention can be very conveniently prepared'bythe reactionof piperazine with a higher alkyl alb'lating reagent. The following preparation will serve to illustrate a method for preparing a representative compound.

Lauryl pipcrazine hildrobromidc A solution of .1 mol of lauryl bromide and .1

mol of piperazine in anhydrous ethanol was boiled under reflux for flve hours and the alcohol then removed by distillation. The product was a soft paste which dissolved in water to give a soapy solution.

Instead of lauryi bromide we can use other alkylating agents, such as octyl iodide, myristyl chloride, cetyl chloracetate, chlor-ethyl myrlstyl ether, beta-chlor-ethyl palmitate, etc., it only being required that the alkylated agent employed We prefer to use these compounds in the form of their hydrohalide salts since .they are either water soluble or readily dispersible in aqueous solutions. On the other hand, it is not necessary that they be used in the form of hydrohalide salts and satisfactory results can be obtained using the free base in our process provided that satisfactory dispersion and distribution is ei'fected. It is, of course, understood that salts other than the hydrohalide salts may be prepared, such as for example, nitrates, acetates, formates, other salts of low molecular weight organic acids and salts of aromatic sulfonic acids, such as for example, benzene suli'onic acid or p-toluene sulfonic acid salts.

While, as stated heretofore, the present invention is not limited to the treatment of any particular ore material, it has been found to be well suited for fr'oth flotation of silica from phosphate rock and is the preferredembodiment of the invention. In the processes of removing silica from phosphate rock, the conditions are such that practically complete removal of the silica must be accomplished in order to produce a salable phosphate material. It is therefore an'advantage of this invention that our reagents not only eflect satisfactory removal of the silica but are also economical in amounts used. The quantities required range from 0.2 pound per ton of ore dependingupon the particular ore and the particular reagent. The invention is not, however, limited to such quantities.

The reagents of the present invention may be used alone or in mixtures with other promoters.

They may likewise be used in conjunction with other cooperating materials such as conditioning reagents, oily or fat materials such as hydrocarbon oils, fatty acids, or fatty acid esters.

These new reagents are also adaptable for use in any of the ordinary concentrating processes such as flim flotation, tabling, and particularly in froth flotation operations. The ore concentrating processes employed will depend upon the particular type or kind of ore which is beins processed. For example, in connection with phosphate rock, relatively coarse phosphate bearing material, for example 28 mesh and larger, can be very economically concentrated by using these reagents in conjunction with a material such as fuel oil or pine oil and subjecting to concentration by the use of tables or by fllm flotation. The 28 phosphate rock material is best concentrated by means of froth flotation employing these improved silica promoters.

When the reagents of the present invention are employed as promoters in the froth flotation of silica from phosphate rock, which is the preferred embodiment thereof, the condition may be varied in accordance with procedures known to those skilled in the art. The reagent may be employed in the form of aqueous solutions, emulsions, mixtures, or solutions in organic solvents, such as alcohol and the like. The reagent may be introranges andfloating each size separately as described in the U. 8. Patent No. 2,156,245, the very complete removal of the slime prior to flotation which is also an aid to better results as pointed out in the Erickson application, Serial No. 325,011

flied March 20, 1940, and the Mead and Maust' application Serial No. 320,121 filed February 21, 1940, which describes a process for classifying and desliming phosphate flotation feed by means -of a hindered settling classifier and which deslimed feed is well suited for treatment in accordance with this invention.

This invention will be further illustrated by the following specific tests which are illustrations of the preferred embodiments thereof, but is not to be strictly limited thereby.

Flotation tests as follows were made on a sample of Florida phosphate rock from the Old Colony Mine near Brewster. A flne flotation feed (-35 +200 mesh) was produced by scrubbing. polishing, and desliming until the ore material was substantially free of slimes.

Separate GOO-gram samples of the deslimed flotation feed were diluted to 22% solids with water and transferred to a laboratory size Fagergren flotation machine. The particular reagent a. The acetate of the reaction product of piperazine and oleic acid.' b. The hydrochloride of the reaction product of piperazine and oleic acid.

oil fatty acids.

or reagent combination was then added and conditioned with the pulp for three seconds. Air was then admitted to the machine and the resulting concentrate froth was collected until the froth became barren. The flotation test products were then flltered, dried, weighed, and assayed. The metallurgical data obtained in these tests are presented in Table I.

where n represents a higher alk'yl radical and salts of such compounds to be effective in pro- ,moting a substantially complete separation of the ,stituents, the process which comprises carrying Table I Concentrate 'lailing Feed Test Lbalton per cent R ents insol. Per cent Peicen g g Per cent Per cent 2 2 w s feed wt. insol. SOL wt. insol. mm].

1 so. as so. so as. 92 so. 14 43. i0 14. is 8:3 2 59.53 mm 88.00 oeso 33.30 260 g-gg a 59. 49 60.13 94. a4 95. 39.87 e. 94 :92,

c. The hydrochloride oi the reaction product of piperazine and coconut When the rake classifler sands such as those. 2:,

produced from the tailings at the Valley Forge- Cement Company plants are treated by flotation using our reagents, the alumina in the form of mica,is removed in part from the silicious material and a cement product is produced which has greatly improved properties. 7

In the treatment of iron ores we have found that our reagent may be employed in flotation processes for removing the silica therefrom and the tailings resulting from such processes are much higher in iron content than concentrates produced by the conventional soap flotation of the iron minerals.

What we claim is:

1. In ore concentrating processes utilizing differential surface wettability principles of separating acidic ore materials from other ore constituents, the process which comprises carryin out the concentration operation in the presence of a suiflcient amount of a substance selected from the group consisting of those represented by the following formula:

NH HaC( C H: Hal! H:

where X is a member of the group consisting of higher alkyl radicals, an alkylol ester radical, higher molecular weight carboxylic. acyl radicals and salts of such compounds to be eifectivein. promoting a substantially complete separation of the acidic materials from the remainder of the ore.

2. In ore concentrating processes utilizing diffei'ential surface wettability principles of separating acidic ore materials from other ore consti tuents, the process which comprises carrying out the concentration operation in the presence of a suflicient amount of a substance selected from the group consisting of those represented by'the following formula:

Bri l Us Y i out the concentration operation in the presence of a suflicient amount of a substance selected from .the group consisting of those represented by the following formula:

where R represents a higher molecular weight carboxylic acyl' radical and salts of such compounds to be eifective in promoting a substantially complete separation of the acidic materials.

from the remainder of the ore.

4. In the froth flotation process of separating.

acidic silicious gangue from non-metallic ore values, the step which comprises subjecting the ore to froth flotation in the presence of a sufflcient amount of a product selected from the group consisting of those represented by the following formula:

1110 CHa Hs I H) i where X is a member of the group consisting of flcient amount of a product selected from thegroup consisting-of those represented by the following formula:

where R'represents a higher alb l radical and where R represents a higher molecular weight carboxylic acyl radical and salts oi such com- 7 pounds to be eflective in promoting a substantially complete separation of the acidic materials from the remainder oi the ore.

7. In the froth floation process 01 separating acidic silicious gangue from phosphate ore values. the step which comprises subjecting the ore to froth flotation in the presence or a sumcient amount of a product selected lrom the group consisting of those represented by the following formula:

HaC CHl I Hg H:

where X is a member of the group consisting of higher allwl radicals. an allwlol ester radical. higher moleculanweightcarboxylic acyl radicals and salts of such compounds to be eflective in promoting a substantially complete separation of theacidic materials from the remainder of the ore. v

8. In the froth flotation process of separating acidicsiiiciousgangue from phosphate ore values,

the step which comprises subjecting the ore to froth flotation in the presence or .a'sufllclent amount or a product selected from the group consisting of those represented by the following. 50

formula:

where R represents a higher alkyl radical and salts of such compounds to be eflective in promuting a substantially complete separation of theacidic materials from the remainder of the I ore.

9. In the iroth flotation process of separating acidic silicious gangue from phosphate ore values, the step which comprises subjecting the ore to froth flotation in the presence of a sufllcient amount of a product selected from the group consisting of those represented by the following formula:

Ha H:

where R represents a higher molecular weight carboxyllc acyl radical and salts or such compounds to be eflective in promoting a substantially complete separation of the acidic materials from the remainder of the ore.

10. In the flotation process or separating acidic siliclous gangue from phosphate ore values, the stepwhich comprises subjecting the ore to froth flotation in the presence of a suillcient amount of the oleic acid acyl derivative of piperazine to be eflective in promoting a substantially complete separation of the acidic materials from the remainder oi the ore. I 11. In the flotation process of separating acidic siliclous' gangue from phosphate ore values. the step which comprises subjecting the ore to froth flotation-in the presence of a sufllcient amount of the coconut oil fatty acid acyl derivative 01 piperazine to be eflective in promoting a substantially complete separation of the acidic materials from the remainder oi the ore.

12. In the flotation process of separating acidic silicious gangue fromphosphate ore values} the step which comprises subjecting the ore to froth flotation in the presence or a sumcient amount of lauryl piperazine hydrobromide to be eflective in promoting a substantially complete separation of the acidic materials from the remainder oi the ore.

DAVID W. J'AYNE, Jr. a HAROLD M. DAY.

STEPHEN E. ERICKSON. 

